Shaped charge engine

ABSTRACT

A shaped charge engine includes an annular blast-forming chamber formed by joining inner and outer housings. A central through hole in the inner housing allows exhaust gases to exit. The outer housing comprises a generally round disk with an inner conical concave depression and through holes for the insertion of fuel and ignition. The blast chamber is preferably taper-conical in shape, wider at the base, and gradually decreasing in cross-sectional area as it rises to the apex. This construction forms a circular pinch point or throat toward the apex that produces a primary or first stage compression area. A secondary compression zone is created at the apex of the outer housing, just beyond the throat, producing hypersonic gases as generally opposing exhaust streams collide and are forced to exit the through hole in the inner housing. The collided streams propel a turbine rotor to turn a shaft.

RELATED APPLICATIONS

[0001] This application is continuing from the application of the samename filed Mar. 2, 2000, with the Ser. No. 09/517,130.

FIELD OF THE INVENTION

[0002] The present invention relates to pulsed hypersonic compressionwaves and more particularly to shaped charge devices using pulsedhypersonic compression waves to create thrust.

BACKGROUND OF THE INVENTION

[0003] In propulsion devices such as jet engines and rocket engines,propulsion thrust is obtained by high-speed exhaust flows. Conventionaljet engines obtain the high-speed exhaust by combustion products of fueland air, while rocket engines obtain the high-speed exhaust by internalcombustion products of fuel and oxidizer. The high pressure combustionproducts are forced through a restrictive orifice, or nozzle, to obtainthe high-speed exhaust flow.

[0004] Several problems are inherent in the conventional systems. Thecombustion in both jet and rocket engines must contain extremely highinternal pressures and are therefore limited by constriction materialstrength. As the internal combustion pressure increases, the combustionchamber wall must increase in thickness to contain the pressure,increasing the combustion chamber weight proportionally and limiting thedesign. Also, as the exhaust nozzle diameter is reduced to increaseexhaust speed, cooling the engine and nozzle becomes increasingly moredifficult. In addition, pulsed engines are unable to evacuate thecombustion products in a short time moment, thus limiting the firingspeed.

[0005] Furthermore, as internal pressure in the combustion chamberincreases, higher fuel and oxidizer inlet pressures are required tointroduce fuel and oxidizer into the combustion chamber, requiringheavier weight pumps that operate at higher horsepower. One example ofsuch limitations on present engines is seen in the phase two main spaceshuttle engine. The engine requires 108,400 horsepower to drive the fueland oxidizer pumps alone. Inlet pressures exceed 6,800 psi in order toobtain an internal combustion chamber pressure to only 3,260 psi with acombustion chamber to nozzle ratio of 77 to 1.

[0006] The huge plume of fire trailing the shuttle and other rockets iscaused by incomplete combustion of the fuel and oxidizer prior toexiting the exhaust nozzle. The fuel and oxidizer igniting outside theengine provide virtually no thrust and are thus wasted. The above spaceshuttle engine example requires 2,000 pounds of fuel and oxidizer persecond to obtain 418,000 pounds thrust at sea level. Furthermore, thecontinuous ignition of present engines causes high heat transfer toengine parts, particularly the nozzle orifice, and the high heattransfer requires the use of costly exotic materials and intricatecooling schemes to preserve the engine structure.

[0007] Prior efforts to improve the engine design focus on variouscomponents, including the nozzle. For example, U.S. Pat. No. 6,003,301to Bratkovich et al., entitled “Exhaust Nozzle for Multi-Tube DetonativeEngines” teaches the use of a nozzle in an engine having multiplecombustor tubes and a common plenum communicating with the combustortubes. Accordingly, Bratkovich et al. teach that the common plenum and acompound flow throat cooperate to maintain a predetermined upstreamcombustor pressure regardless of downstream pressure exiting theexpansion section.

[0008] While the prior art addresses many aspects of propulsion devices,it does not teach the use of a shaped charge in a jet or rocket engine.A shaped charge is generally defined as a charge that is shaped in amanner that concentrates its explosive force in a particular direction.While the general theory behind shaped charges has been known for manyyears, the prior art has restricted the use of shaped charges towarheads and certain other expendable detonation devices. In a typicalwarhead, the shaped charge directs its explosive forces forwardly, inthe direction the warhead is traveling, by igniting moments before orsubstantially simultaneously with impact. The highly concentrated forcecan be used to create a cheap, lightweight armor-piercing device.Examples of shaped charge devices are described in U.S. Pat. No.5,275,355 to Grosswendt, et al., entitled “Antitank Weapon For Combatinga Tank From The Top,” and U.S. Pat. No. 5,363,766 to Brandon, et al.,entitled, “Ramjet Powered, Armor Piercing, High Explosive Projectile.”Shaped charges in such devices are not used to provide propulsion.

[0009] Similarly, current engines configured to drive a turbine do notemploy shaped charge engines. One example of a pulsed turbine engine isdisclosed in U.S. Pat. No. 6,000,214 to Scragg, entitled “DetonationCycle Gas Turbine Engine System Having Intermittent Fuel and AirDelivery.” Scragg teaches a detonation cycle gas turbine engineincluding a turbine rotor within a housing. Valveless combustionchambers are positioned on either side of the rotor to direct combustiongases toward the turbine blades. The two combustion chambers alternatelyignite the mixture of fuel and oxidizer to cyclically drive the turbine.While Scragg discloses a useful engine, efficiency, horsepower per unitof engine weight, and other performance parameters could be greatlyimproved. For example, the Scragg device constructed to deliver 200 hpwould require a 560 cubic inch combustion chamber and would weigh 262pounds, while a 200 hp engine using a shaped charge as in the presentinvention would require a combustion chamber of only 18 cubic inches andwould weigh only 70 lbs.

[0010] There is therefore a need for a shaped charge propulsion devicethat provides substantially improved performance than prior art devices.

SUMMARY OF THE INVENTION

[0011] The present invention provides a shaped charge engine thatovercomes many limitations of the prior art. The apparatus includes ablast-forming chamber comprising an inner annular charge forming housinghaving a conical convex projection that forms the inner walls of theblast-forming chamber. A central through hole is provided to allowexhaust gases to exit. An outer housing comprises a generally round diskwith an inner conical concave depression and through holes for theinsertion of fuel and ignition. The two housings are joined byconventional means such as welding or bolts. The resulting chamberformed by joining the two housings is taper-conical in shape, wider atthe base, and gradually decreasing in cross-sectional area as it risesto the apex. This construction forms a circular pinch point or throattoward the apex that forms the primary or first stage compression area.A secondary compression zone is created at the apex of the outerhousing, just beyond the throat. Hypersonic gases exit the through holein the inner housing.

[0012] In accordance with further aspects of the invention, a directedthrust is formed in a pulsed manner using a contained bum that starts ata peripheral base area and is directed in a tapered-conical shape thatforms a primary compression area adjacent the apex of the conical shape.The compressed bum thereafter continues to the apex of thetapered-conical shape, creating a high-speed convergence or secondarycompression zone before being exhausted. This construction provides amore complete ignition within the chamber, enhancing efficiency bycapturing more of the energy before it leaves the engine. It also allowsfor the combustion products to exit the primary combustion chamber morerapidly, thus allowing a higher pulse rate of firing while maintainingthe high compression exhaust flows by not compressing exhaust productsto final velocity internally.

[0013] In accordance with other aspects of the invention, the engineincludes a sensor to determine the ambient air density, allowing theengine to selectively consume air or oxidizers, as appropriate.

[0014] In accordance with still further aspects of the invention,inexpensive conventional fuels, such as gasoline, acetylene, butane,propane, natural gas, and diesel oil are mixed with air or an oxidizerinto a combustible mixture and infused under positive pressure into thehollow blast-forming chamber in a manner that permits positive shutoffbetween a series of induction cycles to accommodate ignition cycles.

[0015] In accordance with yet other aspects of the invention, an igniterignites the combustible mixture initiating a blast wave or pulse at thebase of the hollow blast-forming chamber. As the blast wave or pulseadvances into a gradually compressed blast-forming chamber, additionalmass may be injected into the blast chamber, thereby increasing themomentum of the blast wave. Explosion products are compressed by thegradually decreasing cross sectional area of the blast-forming chamber.The increasing pressure drives the blast wave into a primary compressionzone formed by an annular restriction between the truncated end of acentral conical projection and an opposing truncated hemispherical ordomed inner surface of the outer housing.

[0016] Compression of the blast wave into this annular restrictioncreates a high-speed radial flow of explosion products toward the centerof the truncated hemispherical or domed surface. The opposing high-speedradial streams of explosion products converge at the center of thetruncated hemispherical or domed surface creating a secondary zone ofincreased compression of the explosion products. Confluence of mass andkinetic energy in the secondary compression zone forms the explosionproducts into hypersonic gases that exit in a controlled blast directedthrough an exhaust port centrally located at the apex of the centralconical projection. The resulting high pressure hypersonic exhaust isexpelled in a directed blast from the exhaust port without the need foran exit nozzle.

[0017] In accordance with still another aspect of the invention, theexit velocity of the combustion products and ejecta is controlled byincreasing or decreasing the size, length, diameter, and depth angle ofthe blast chamber, and adjusting fuel-oxidizer mixtures.

[0018] In accordance with still further aspects of the invention, thecontrolled blasts formed in the blast-forming chamber are repeatable bythe serial infusion and ignition of additional charges of thecombustible mixture. Furthermore, in repeating pulsed modes, the blastpower and frequency are throttle controllable by increasing ordecreasing the flow rate of the combustible mixture or adjusting thecycle rate independently of the mixture flow rate.

[0019] In accordance with yet another aspect of the invention, theengine is operated in a pulsed mode along a continuum between an aerobicor air-breathing jet mode and an anaerobic or non-air-breathing rocketmode. Accordingly, fuel is mixed with air, oxidizer, or any combinationof the two in any relative concentration. The relative concentrations ofair and oxidizer in the combustible mixture is dynamically adjusted intoa blend of air and oxidizer, which may be a function of oxygenconcentration in the ambient atmosphere.

[0020] In accordance with further aspects of the invention, theparticular geometry of the shaped charge engine may be varied, whilestill retaining the inventive aspects, including primary and secondaryconvergence zones. Accordingly, the cross-sectional shape may beannular, square, rectangular, triangular, or a variety of other formsdepending on the desired results and the space available to house theengine in the vehicle to be propelled.

[0021] In accordance with still further aspects of the invention, theexhaust gases collide at a secondary convergence zone to createhypersonic exhaust. The opposing streams of gases may originate inchambers that are substantially opposite one another and at leastpartially orthogonal to the direction of travel. Alternatively, theblast chamber may be configured such that the explosive products travelin an acute or an obtuse angle with respect to the direction of travelbefore reaching the throat and the secondary compression zone.

[0022] In accordance with additional aspects of the invention, the angleat which the exhaust gases converge may be dynamically controlled duringoperation of the engine. The generally opposed sides of the generallyannular blast-forming chamber may be hinged to allow the chambers to bemoved fore and aft to adjust the angle of convergence.

[0023] In accordance with yet other aspects of the invention, thecross-sectional area of the throat or pinch point may be increased ordecreased. By decreasing the size of the throat area, the exhaust gasestravel at a higher velocity, creating a relative spike in the exhaustvelocity and therefore the thrust. Conversely, by increasing the throatsize, the exhaust gases exit more uniformly and at a lower relativevelocity.

[0024] In accordance with other aspects of the invention, the engine maybe used to provide direct thrust to propel a rocket, aircraft, personalwater craft, or other vehicle.

[0025] In accordance with still other aspects of the invention, theexhaust gases created by the engine may be used to drive a turbine thatis used to propel the vehicle. In such an embodiment, the engine may,for example, be used to power a car.

[0026] In accordance with still further aspects of the invention, thepressure, exhaust, pulse, or heat produced by the shaped charge enginemay be used in a wide variety of applications, including, for example,vehicle propulsion, pest control, demolition, cutting tools, etchingtools, heating tools, spraying tools, high-speed guns, generators,boilers, and closed-system pressure devices.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The preferred embodiment of the present invention is described indetail with reference to the following drawings.

[0028]FIG. 1 is a cross-sectional view of a shaped charge engine,including a blast-forming chamber, formed in accordance with a preferredembodiment of the present invention;

[0029] FIGS. 2A-C is a cross-sectional view of several representativeshapes of a blast-forming chamber formed in accordance with the presentinvention;

[0030] FIGS. 3A-C is a cross-sectional view of several representativeorientations of a blast-forming chamber formed in accordance with thepresent invention;

[0031]FIG. 4 is a cross-sectional view of two alternate configurationsfor the throat of an engine formed in accordance with the presentinvention;

[0032]FIG. 5 is a representative view of a switchable jet and rocketengine formed in accordance with the present invention;

[0033]FIG. 6 is a representative view of a pulse driver engine formed inaccordance with the present invention;

[0034]FIG. 7A is a side view of a rotary centrifugal throttle valveformed in accordance with the present invention;

[0035]FIG. 7B is a top view of rotary centrifugal throttle valve formedin accordance with the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0036] General Construction of the Shaped Charge Engine. FIG. 1schematically illustrates in cross-section a device constructed inaccordance with the present invention for dynamically compressing anddetonating a combustible mixture to form a shaped compression wave.Reference numeral 10 generally refers to a shaped charge engine. Theengine 10 includes a hollow blast-forming chamber 3 formed between anouter charge forming housing 2 and an inner charge forming housing 1.The outer charge forming housing 2 is generally round-conical in shapeand includes a centrally located dome shaped portion at the apex to forma concave “cup” or “bowl” shape.

[0037] The inner charge forming housing 1 comprises a generally flatplane transitioning to a centrally located generally conical-shapedprojection 7. The projection 7 extends radially inward and upward towardthe outer housing 2. The projection 7 is truncated below the tip to forma centrally located generally circular opening at the smaller end of thecone which is nearest the outer housing 2 when the inner housing 1 andouter housing 2 are joined. From the perspective of exhaust gases Etraveling from the tip of the projection 7 through the opening and outthe engine, the projection 7 thus forms a generally cylindrical openingthat flares outward into a generally conical opening at the exit.

[0038] The inner charge forming housing 1 is joined to the outer chargeforming housing 2 so that the projection 7 extends toward the outerhousing 2. The outer charge forming housing 2 and inner charge forminghousing 1 are joined along their respective outer peripheral edges toform hollow blast-forming chamber 3 in the space between the innerhousing 1 and outer housing 2. The inner and outer charge forminghousings 1 and 2 are joined, for example, by a weld 6, or by othercompression means such as bolts or rivets.

[0039] The housings 1 and 2 are formed of materials capable ofwithstanding the heat and pressure of the ignition, detonation, andcompression of the controlled combustion. Any of a variety of materialstypically used in the construction of rocket engines may be used for thepresent invention, including, for example, steel, stainless steel, ortitanium. Preferably, the material of inner charge forming housing 1 issufficiently thick to withstand the heat and pressure without externalsupport.

[0040] A plurality of fuel injectors 5 and igniters 4 project throughthe outer housing 2 and into the chamber 3. The injectors 5 infuse fuel,air, and oxidizer into hollow blast-forming chamber 3. The preferredcombustible mixture is, for example, formed of any conventional fuelthat, when mixed with air, oxidizer, or a combination of both, forms acombustible mix. The fuel is optionally any airborne combustiblematerial such as Hydrogen or other flammable gases; an inexpensiveliquid spray such as butane, propane, gasoline, acetylene, or naturalgas; a combination of vapor and liquid drops such as diesel oil;airborne solid particles; or another combustible mixture that burnsrapidly enough to accomplish dynamic compression and detonation. Thefuel is preferably mixed with a proportioned amount of air or oxidizerfor complete combustion.

[0041] The igniter 4 is, for example, a conventional spark plug poweredby a spark generator, glow-plug, piezo-electric spark gap or anothersuitable ignition device. In accordance with alternate embodiments ofthe invention, the igniter 4 is a hot plasma jet generated by a plasmajet generator (not shown) and directed into the ignition region of thehollow blast-forming chamber 3. Other fast and reliable devices forinjecting flames or sparks essentially instantaneously into the ignitionregion are within the scope of the present invention as alternativeignition devices.

[0042] While the injector and igniter are preferably constructed suchthat they project through the outer housing 2 into the blast-formingchamber, either or both of the injector 5 and igniter 4 may beperipherally mounted in the inner charge forming housing 1 or in thespace separating the inner and outer housings 1 and 2 (i.e., along theweld 6), so long as they extend into the ignition region of the hollowblast-forming chamber 3.

[0043] The combustible mixture injector 5 is any conventional injectionsystem suitable for providing a controllable flow of the combustiblemixture, including, for example, conventional fuel injectors andcarburetors. Conventional carburetors used in conjunction withturbochargers allow the mixing of a wide variety of fuels with air forinjection into the hollow blast-forming chamber 3.

[0044] The timing of the fuel injection and ignition, and therefore thetiming of the combustion, is controlled by a control system (not shown)including fuel, air, and oxidizer valves. A valve port is formed at thecombustible mixture injection point if a carburetor or pressurizedbottled or liquid fuel is used to practice the invention. A valve forthe valve port is operated to admit the combustible mixture into thehollow blast-forming chamber 3. The valve is a solenoid valve in eachcase, although other valves may be used, such as any of a rotary, disc,poppet or drum valve or any other device that allows air, oxidizer andfuel to be injected into the chamber 3 under positive pressure and thatallows for a positive shutoff between induction cycles to accommodatethe ignition cycle. If necessary, increased pressure from combustion inthe hollow blast-forming chamber 3 operates over an area of the valve toclose the valve and limit ignition injection into the carburetor.

[0045] The blast-forming chamber 3 includes only a single annularopening at the center. This opening comprises the area between the innerhousing projection 7 and the outer housing 2. The substantiallyrestrictive opening creates a restrictive pinch point that forms aprimary or first stage compression area. A high-speed convergence orsecondary compression zone 9 is created at the apex of the outer housing2 generally at the center of the annular region defining the throat andsubstantially along the axis of the inner and outer housings 1 and 2.

[0046] General Operation of the Shaped Charge. The outer charge forminghousing 2 is adapted to accept the introduction of a combustible mixtureinto the hollow blast-forming chamber 3 near the outer periphery of thebase of the hollow blast-forming chamber 3. The blast-forming chamber islarger in cross-sectional area, at least relative to the throat, at thelocation of fuel injection and ignition. Because multiple fuel injectors5 and igniters 4 are spaced along the periphery of the inner and outercharge forming housings 1 and 2, there are several locations within thechamber 3 at which combustion takes place. Preferably, combustion occursat generally opposing sides of the chamber 3.

[0047] In an embodiment in which both air and oxidizers are bothavailable, for example a combined jet/rocket engine, air is burned withfuel in sufficiently dense atmospheres to accommodate the fuel loadwhile air is available. An air mass sensor (e.g., hot wire anomometry)or other sensor is coupled to a controller (not shown) that determinesthe amount of air available. The controller causes the inlet RAM port toopen as air mass decreases so that sufficient oxygen enters the chamber3. After the controller determines that air mass is too low, the airinlet stays open and the oxidizer port begins to open, causing oxidizerto enter the chamber 3. During the transitional period in which air isavailable but either not ideal or sufficient, both air and oxidizer areused. When the air density is too low, the outside air inlet closes andoxidizer alone is used for combustion. Thus, the device is operatedaerobically in a jet mode, anaerobically in a rocket mode, or in any ofcombination of jet and rocket modes.

[0048] The igniters 4 and injectors 5 are located near the periphery ofthe blast-forming chamber 3, causing ignition to be started relativelynear the periphery of the annular chamber 3. Because multiple igniters 4are spaced around the chamber, ignition also takes place substantiallysimultaneously at several locations around the chamber. Each of themultiple injectors 5 simultaneously injects an appropriate amount of thecombustible mixture into the chamber 3 under positive local pressurerelative to the pressure inside the remainder of the hollowblast-forming chamber 3. The injector 5 is sealed or closed followingthe injection cycle, creating a barrier or block between the hollowblast-forming chamber 3 and the fuel and the air or oxidizer.

[0049] After sealing the injectors 5, each of the multiple igniters 4essentially simultaneously ignites the charge of combustible mixture,causing the detonation (or pulse) along essentially the entire outercircumference of the base of the hollow blast-forming chamber 3. As theflame front or pulse advances toward the apex of the hollowblast-forming chamber 3, additional mass can be injected into thechamber 3 to increase the mass and therefore the momentum of the blastwave. Preferably, the injected mass is a safe mass such as water or aninert slurry, although the mass may alternatively be a combustible mass,including additional fuel. The explosion products are increasinglycompressed by the gradual reduction in cross sectional area at thethroat, or the apex of hollow blast-forming chamber 3. As the flamefront advances toward the throat, primary or first stage compression isachieved by back pressure forcing the flame front essentiallysimultaneously into all areas of the throat. This forcing of the flamefront through the throat creates a high-speed inwardly radial flow ofexplosion products toward the apex of the inner surface of the outercharge forming housing 2.

[0050] The high-speed explosion products stream exits the chamberthrough the throat and advances inwardly causing high-speed gases toconverge near the inner surface 8 and at the center line 9 of the outercharge forming housing 2. The convergence creates, by the confluence ofmass and kinetic energy, a secondary compression zone that forms theexplosion products into hypersonic gases before their exhaustion in acontrolled blast directed through the exhaust port. The resulting highpressure hypersonic exhaust E is expelled in a directed blast from theexhaust port without the need for an exit nozzle. The above descriptionrepresents a single firing cycle, which is useful in many applications.The engine may alternatively be operated in a pulsed mode by repeatingthe above firing cycle.

[0051] The shaped charge engine is controllable using a throttle thatmay vary the fuel, air, and oxidizer volume. In a typical rotating diskvalve that serves as a throttle, two holes are spaced 180 degrees apartto allow for injection of fuel only when the holes are aligned with thefuel lines as the disk rotates, for example at 100 RPM. As the diskrotation speed increases, the time moment of hole alignment decreases,providing a smaller amount of fuel to be injected per pulse. Conversely,decreasing the rotation rate will cause greater amounts of fuel to beinjected per pulse.

[0052] Alternate Embodiments of the Shaped Charge Engine. While thegeneral construction and operation of the shaped charge engine of thepreferred embodiment is discussed above and shown in FIG. 1, theconstruction may be varied, consistent with the present invention. Incertain applications, it may be desirable to construct the shaped chargeengine with an alternate geometric shape. For example, with reference toFIG. 2, the cross-sectional geometric shape may be varied in alternateembodiments. The generally circular or annular shape depicted in FIG. 2Acorresponds to the circumference of the blast chamber 3 of the preferredembodiment shown in FIG. 1. Alternate embodiments are depicted in FIGS.2B and 2C, showing rectangular and triangular designs, respectively.

[0053] The design of the preferred embodiment, shown in FIG. 2A, is anideal shaped charge engine having exhaust products that converge at thecenter simultaneously. The rectangular embodiment of FIG. 2B is somewhatless efficient but still produces exhaust products that collidesubstantially simultaneously because exhaust products travel likedistances from opposing sides before reaching the secondary compressionzone. The triangular embodiment of FIG. 2C is quite inefficient, withuneven distances from the periphery of the combustion chamber 3 to thesecondary compression region, producing lower exhaust velocities andless thrust than the circular embodiment of FIG. 2A. Still other shapesof a generally convex polygonal nature may be used, consistent with thisinvention.

[0054] Just as the cross-sectional shape of the blast-forming chamber 3may be varied, so may the orientation of the blast-forming chamber bealtered. The general orientation of the preferred embodiment is depictedin FIG. 3A. In the embodiment of FIG. 3A (which may be characterized as“concave”), the exhaust products travel toward the throat from a pointgenerally upstream of and somewhat orthogonal to the final exhaustdirection. As the exhaust products pass through the throat, they collidewith the outer housing 2 and gases emerging from opposite sides at thesecondary compression zone, producing hypersonic exhaust in a directionsomewhat opposite the direction of travel through the throat.

[0055] In an alternate embodiment, as depicted in FIG. 3B, theblast-forming chamber is substantially flat, so that the exhaustproducts travel through the throat in a direction generally orthogonalto the final exhaust direction. In yet another embodiment, as depictedin FIG. 3C, the blast-forming chamber is in a convex configuration, sothat the exhaust products travel through the throat in a direction thatforms an obtuse angle with the final exhaust direction. Likewise,additional orientations not depicted in FIG. 3 are possible.

[0056] Among the three embodiments depicted in FIG. 3, the embodiment ofFIG. 3A can be considered a high pressure spike motor. The change indirection of the exhaust gases just beyond the throat causes “thermalstacking” of the gases just prior to exit. The result produces apowerful but brief spike of thrust as the gases exit the engine. Whilethe total masses of exhaust products are the same in each embodiment,the thrust characteristics differ. Thus, the embodiment of FIG. 3B willproduce a relatively weaker, longer thrust moment, while the embodimentof FIG. 3C will produce a more even exhaust flow with a relativelysmaller spike.

[0057] Depending on the environment and desired performance, it may beuseful to construct a single engine in which the blast chamberorientation can be dynamically varied from a convex orientation (such asin FIG. 3C) to a concave orientation (such as in FIG. 3A). In thepreferred embodiment, particularly when used as a pulse jet/rocketengine as discussed further below with reference to FIG. 5, the shapedcharge engine may be hinged and dynamically adjustable to create varyingblast chamber orientations.

[0058] With reference again to FIGS. 3A-C, outer housing hinge pointsH1, H2 are indicated at locations that allow for adjustment of theorientation of the shaped charge engine. Thus, by pivoting the outerhousing 2 at the location of the outer housing hinge points H1, H2, theorientation of the shaped charge engine may be changed along a continuumfrom a generally convex orientation (such as in FIG. 3C) to a concaveorientation (such as in FIG. 3A). Because the blast chamber 3 ispreferably a continuous annular ring, the inner and outer housings 1, 2comprise a series of plates arranged to slide over and under one anotheras the configuration changes. Alternate constructions are also possible,including for example a combustion chamber that comprises a plurality ofseparate sub-chambers that are adjoining or nearly adjoining one anotherat the most concave and convex positions (as in FIGS. 3A AND 3C) butthat are spaced relatively farther apart from one another in the morehorizontal configurations as in FIG. 3B.

[0059] The throat area may also be varied, consistent with theinvention. With reference to FIG. 4, two alternate embodiments areshown. In FIG. 4A, a low pressure engine is shown having a relativelylarger throat. Alternatively, the embodiment of FIG. 4B includes arelatively smaller throat. Relative to the engine of FIG. 4B, the engineof FIG. 4A will create lower pressure in the combustion chamber 3, lowervelocities through the throat, and a smaller spike in exhaust velocityand thrust.

[0060] Again with reference to FIGS. 3A-C, outer housing hinge pointsH3, H4 are indicated at positions that allow the inner housing 1 to beadjusted swing closer or farther from the outer housing 2. Thus, as theinner housing 1 is pivotally moved toward the outer housing 2, the sizeof the throat is decreased, producing a smaller “pinch point.”Conversely, the inner housing 1 can be rotated outward, away from theouter housing 2, producing a larger throat. In the case of both theadjusted orientation and adjusted throat area, the hinging action isbest accomplished by hydraulics, screw-drive, or other such devices thatcan move metal plates and withstand the substantial pressures producedin the blast-forming chamber 3.

[0061] Use as a Switch able Pulsed Jet/Rocket Engine. A presentlypreferred application of the shaped charge engine is depicted in FIG. 5,which schematically illustrates a switchable pulsed jet/rocket engine.The switchable pulsed jet/rocket engine of FIG. 5, generally indicatedby reference numeral 100, includes a shaped charge engine in accordancewith that of FIG. 1, although it is shown in a concave orientation as inFIG. 3C.

[0062] The engine begins operation from a cold start at low altitudes ina pulsed jet mode. Pulses of fuel and oxidizer are fed from sources offuel 101 and oxidizer 108 to the shaped charge combustion chamber 106via separate fuel and oxidizer lines 102, 110, each of which iscontrolled by a solenoid valve 104 a, 104 b. An igniter 112 ignites thefuel and oxidizer mixture, creating a blast and attendant high pressurewithin the chamber 106. When the rotary valve is in use (principally injet mode), the igniter is controlled by a fixed timing ignition devicesuch as, for example, points typically found in an automobiledistributor, magneto or battery assisted magnetic pickups, or lightsensitive relays. When direct fuel and oxidizer injection are used (inrocket mode), the igniter is controlled by computer processor initiatedtiming pulses.

[0063] By opening a solenoid valve 104 c on an exhaust bypass line 114,pressurized exhaust products are allowed to flow to an exhaust-driventurbine 116, causing it to rotate. The exhaust-driven turbine 116 isconnected to a compressor 118, a fuel pump 120, and a centrifugalthrottle valve 122, each of which is configured to rotate together as aunit. While an ordinary rotating disk may be used consistent with thisinvention, in the preferred embodiment the centrifugal throttle valve122 (discussed in greater detail below with reference to FIG. 7) is usedto provide superior control, particularly in fixed inlet pressureconditions. As the unit rotates, compressed air 126 collected via an airscoop 128 is delivered through an air line 130 while fuel is deliveredvia a fuel line 132 to the centrifugal throttle valve 122. Thecentrifugal throttle valve 122 allows air and fuel to pass through thevalve by opening and closing multiple apertures that are cyclicallyaligned and mis-aligned as it rotates.

[0064] Fuel and air, after passing through the centrifugal throttlevalve 122, are mixed in a mixing manifold 134 and injected into theshaped charge combustion chamber 106 when the centrifugal throttle valve122 is opened. The centrifugal throttle valve 122 then closes and theigniter 112 ignites the fuel and air (or oxidizer) mixture within thechamber 106 at an ignition point 113. The detonation causes exhaustproducts to travel out the chamber 106.

[0065] The preferred centrifugal throttle valve is shown in side view inFIG. 7A and plan view in FIG. 7B. Previous rotary disk valves havingfixed opening sizes such as are used in prior variable firing rateengines suffer many problems, regardless of the size or shape of theopenings. For example, if the port is sized for low rate firing then thetime during which the openings are aligned decreases as rotationincreases, allowing less air, fuel, or mixture to pass through the valveper pulse. Consequently, higher inlet pressure is required to obtain thecorrect charge volume. On the other hand, if the port is sized for highrate firing, then at low firing rates the disk spins slower, the holesare aligned for longer periods, and an excess amount of air, fuel, ormixture is allowed to pass through the valve. In order to compensate forthe excess and obtain the correct charge volume, lower inlet pressuresand controls are required.

[0066] The rotary centrifugal throttle valve 122 overcomes theseproblems and allows for correct charge volumes at all firing rates whileusing a fixed inlet pressure. The centrifugal throttle valve 122includes a driveshaft 172 having a projection 174 and a disk valvehousing 176 mounted on the driveshaft 172. The disk valve housing 176comprises two halves 176 a, 176 b joined together in conventional meanssuch as welding, lamination, bolts, or screws 184. The two halves 176 a,176 b of the disk valve housing 176 include recessions that, when thehalves are joined, together form inner pockets 178 a, 178 b. The diskvalve housing 176 also includes one or more openings 182 a, 182 bpassing through the disk valve housing 176 substantially overlying theinner pockets. A sliding valve 179 a, 179 b is retained within each ofthe pockets 178 a, 178 b. A further recession within the two halves 176a, 176 b of the disk valve housing forms spring pockets 181 a, 181 bthat retain springs 180 a, 180 b associated with each sliding valve 179a, 179 b. Other devices may be used in the place of the springs 180 a,180 b to bias the sliding valves 179 a, 179 b in a closed position atslower rotation speeds, including other resilient materials orcompression devices. Still further, the sliding valves 179 a, 179 b maybe electronically controlled using hydraulics, worm-drives, or othermechanisms to open and close the valves as a function of rotation rate.While the centrifugal throttle valve 122 is illustrated as having twoopenings 182 a, 182 b, any number of openings may be used, consistentwith the invention. Likewise, the openings 182 a, 182 b are illustratedas having a generally “pie” shape, but may be round, square, or anyother shape.

[0067] With reference more particularly to FIG. 7B, the operation of thecentrifugal throttle valve is illustrated, representationally both athigh and low firing rates. At low firing rates, the disk valve housing176 rotates at a relatively lower rate, causing the spring 180 b to urgethe sliding valve 179 b in a direction radially inward within the pocket178 b. By moving toward the center of the disk valve housing 176, thesliding valve 179 b covers a substantial portion of the opening 182 b,limiting the amount of air, fuel, or mixture that may pass through tothe combustion chamber. Note that the openings 182 a, 182 b arepreferably formed so that the sliding valves 178 a, 178 b cannot fullycover them even when the centrifugal throttle valve 122 is stopped or atits slowest rate of rotation. This arrangement allows air, fuel, ormixture to reach the combustion chamber during start-up and prevents theengine from stalling at the lowest firing rates.

[0068] At relatively higher firing rates, centrifugal forces cause thesliding valve 179 a to compress the spring 180 a farther within thespring housing 181 a. The recession of the spring radially outwardlyuncovers a substantial portion of the opening 182 a, allowing a greateramount of fuel, air, or mixture to pass through to the combustionchamber. In any particular application, the throttle valve may betailored by substituting springs of greater or lesser resistance,altering the opening size or shape, locating the openings farther inwardor outward along the disk housing radius, or increasing or decreasingthe number of openings on the disk valve housing 176.

[0069] While the above discussion and illustration in FIG. 7B depictsone opening 182 a substantially uncovered by the sliding valve 179 a aswould be the case at a high firing rate, and one opening 182 bsubstantially covered by the sliding valve 179 b as would be the case ata low firing rate, this condition is shown on a single valve only forease of illustration and discussion. In practice, each of the openings182 a, 182 b would be covered or uncovered by the sliding valves 179 a,179 b to substantially the same extent at all times.

[0070] The projection 174 on the driveshaft 172 is shown as a triangleshape, offset from the center of the driveshaft 172. The projection 174may alternatively be of any shape, although an irregular shape ispreferred to prevent joining the driveshaft 172 to the disk housing 176out of phase with ignition or other external parts that require timing.The driveshaft 172 is joined to the disk housing 176 by inserting theprojection 174 into a similarly shaped recession 184 within the diskhousing 176. The projection 174 and recession 184 are configured toallow the projection 174 to slide within the recession 184, permittingthe disk housing 176 to move inward or outward along the shaft 172. Athrust washer 186 absorbs the force imparted on the disk housing 176 andensures a tight seal. This construction allows the centrifugal throttlevalve to absorb substantial pressures without damaging the drive motoror other components. Moreover, the sliding arrangement of the projection174 within the recession 184 allows for wear on the thrust washer.

[0071] As the turbine 116, compressor 118, fuel pump 120, andcentrifugal throttle valve 122 continue to rotate, pulses of the fueland air mixture are continually produced and ignited as described above.The solenoid valve 104 c associated with the exhaust bypass line 114 ismodulated (or pulsed) to produce the desired idle speed of the turbineand the engine itself.

[0072] The air scoop 128 is opened or closed automatically via a linearactuator 136. The linear actuator 136 is controlled by an air masssensor 138 that, as discussed above, determines the air mass available.In the preferred embodiment, the air mass sensor 138 essentiallycomprises a heated wire that decreases in temperature as increased airmass flows over the wire during flight. The temperature of the wire isread by a processor (not shown) to determine the magnitude of theexisting air mass. Thus, the linear actuator 136 can, for example, openthe air scoop 128 when the air mass sensor 138 senses a reduced air massavailable, causing more air volume to enter the intake air plenum 140.

[0073] With the engine at idle, the switchable pulsed jet/rocket isready to transition to a pulse jet mode of operation in whichsubstantial thrust is produced. The solenoid valve 104 c on the exhaustbypass line 114 is opened substantially fully, allowing more exhaust gasto flow through the line to drive the turbine 116, causing it to rotatefaster. In turn, the compressor 118, fuel pump 120, and centrifugalthrottle valve 122 rotate faster. Because of the centrifugal forcesproduced by the faster rotation, the centrifugal throttle valve 122automatically opens the valve aperture opening to allow higher air andfuel flows required at rapid pulse rates.

[0074] The high pulse rate fuel and air charges that are ignited by thetimed ignition of the igniter 112 causes detonation wave exhaust streamsto flow from the ignition point 113 within the combustion chamber 106.The exhaust streams flow through the low pressure pinch point at thethroat 142 and converge at a secondary high pressure compression point144 from which they exit as a high pressure hypersonic exhaust flow inthe direction of the arrow 146. The engine is now operating at thehighest thrust setting possible using air and fuel as the inertial mass(and without altering the shape or orientation of the combustion chamber106).

[0075] Greater thrust can be obtained by adding additional mass to thecombustion chamber 106. As noted previously, the additional mass ispreferably a safe mass such as water or an inert slurry. The additionalmass products from the mass injection manifold 148 are injected into thechamber 106 by opening a solenoid valve 104 d located on an additionalmass line 150. The additional mass is injected into the chamber 106between pulses and prior to firing of the igniter 112. The exhauststream automatically accelerates the additional mass out the chamber106. The engine is now at an ultra-high thrust setting; that is, themaximum thrust that can be achieved using fuel, any combination of airand oxidizer, and added mass to produce thrust in the configuration andorientation of the engine.

[0076] As the atmosphere thins, the pressure in the air intake plenum140 diminishes and is sensed by the air mass sensor 138. The air scoop128 is automatically opened by extending the linear actuator 136,causing the air scoop 128 to pivot on a hinge point 152. The additionalvolume of air increases the pressure in the plenum 140 to satisfy theoxygen requirements of the engine until the air scoop 128 is opened toits widest position. As the atmosphere thins further, the air scoopcannot admit a greater flow of air. A computer controller (not shown)coupled to the air mass sensor 138, upon determining that the air scoop128 is open at its widest and the air is too thin, causes one or moreoxidizer valves 154 to open to allow oxidizer to flow into the chamber106. While the oxidizer valves 154 are preferably driven by a controllercontaining a processor, they may alternatively be driven directly byproximity switches associated with the air mass sensor 138 and linearactuator 136. The oxidizer valve 154 allows an increasing amount ofoxidizer to be injected into the blast chamber 106 as the atmospherethins even further.

[0077] When no air or atmospheric pressure is sensed by the air masssensor 138, the engine operates in an anaerobic mode essentially as aspace vehicle. The solenoid valve 104 c on the exhaust bypass line 114closes, causing the turbine 116, compressor 118, fuel pump 120, andcentrifugal throttle valve 122 to stop rotating. Likewise, because thereis no air available, the air intake scoop 128 is closed by retractingthe linear actuator 136.

[0078] Fuel and oxidizer are fed directly to the combustion chamber 106via the fuel line 102 and oxidizer line 110 by timed pulses of thesolenoid valves 104 a, b. All other operations of the ignition,injection of mass, and exhaust are the same as in the air-breathing modeof operation.

[0079] When air becomes available as the engine descends, the air masssensor 138 detects the increased presence of air and allows the airscoop 128 to open so that an aerobic, or jet, mode of operation canagain take place.

[0080] Hinged and gimbaled operation. In the preferred embodiment of thepresent invention, the shaped charge engine is hinged so that theorientation of the combustion chambers can be dynamically altered duringflight. Such a construction is discussed above with reference to FIGS.3A-C.

[0081] In addition, the engine can be gimbaled to allow the direction ofthe exhaust products to be controlled. The outer engine is pivotallymounted on the air/space craft so that the exhaust stream can bedirected. By pivoting the engine, and therefore the exhaust stream, theengine itself provides directional control. In alternate embodiments,the blast-forming chamber 3 may be pivotally mounted while the remainderof the propulsion and control system is fixed. In still anotheralternate embodiment, directional control can be obtained by adjustingthe inner and outer housing hinges H1, H2, H3, H4 in an asymmetricalfashion. Thus, for example, the outer housing hinges H1, H2 can beadjusted to produce a blast-forming chamber having opposing sides thatare in slightly different orientations. Likewise, for example, the innerhousing hinges H3, H4 can be adjusted to produce a throat that isimbalanced on opposing sides. In either configuration, the exhauststream will be directed off-center, providing directional control.

[0082] Use as a Pulse Driver for Other Vehicles. While the shaped chargeengine of this invention is described above as suitable forair-breathing and non-air-breathing applications, it can also be adaptedfor use in applications that always have air available. For example, theshaped charge engine may propel a car or boat, may be used in a tool oras a generator, or may be used in many other applications that will haveair available. The general construction of the shaped charge engine foruse in such atmospheric conditions is shown in FIG. 6. The atmosphericengine includes one or more air intake ports 201 leading to a compressor202. The compressed air is passed through air outlet ports 203 to thecombustion chamber 206 via engine air inlet ports 204. Fuel from a fuelsource (not shown) is injected via fuel injectors 205.

[0083] In the same manner as discussed above, the engine includes aprimary low pressure pinch point at the throat 207 leading to asecondary high compression point 208 that produces a high pressureexhaust stream 209. The fuel and air mixture is ignited by an igniter212 that is illustrated as a spark plug. A drive motor (not shown) isconnected to a drive shaft 215 via a key way or spline 216. In turn, avalve drive extension 214 on the drive shaft 215 is connected to arotary centrifugal throttle valve that operates as described above withreference to FIG. 8.

[0084] The primary difference between the shaped charge engine of FIG. 6and the pulsed jet/rocket engine of FIG. 5 is the inclusion of oxidizerand the ability to open and close air intake scoops. In all otherrelevant respects, the engines of FIGS. 5 and 6 are constructed andoperate in a similar manner.

[0085] Use as a Turbine Driver. The shaped charge engine has beendescribed above as a direct propulsion device. Alternatively, the highcompression, high inertia exhaust stream can drive fixed cycle or freespinning turbines such as those of the Pelton or axial flow type. Oneexample of a detonation cycle turbine engine is shown in U.S. Pat. No.6,000,214 to Scragg. Scragg discloses a turbine rotor driven by theexhaust ports of two combustion chambers on opposite sides of the rotor.The torque produced by the acceleration and rotation of the turbine isput to work in conventional electrical or mechanical means.

[0086] Similarly, the exhaust of a single or any number of shaped chargeengines can be directed toward a turbine. Because the shaped chargeengine of the present invention is far more efficient, however, itproduces a much improved turbine-driving engine.

[0087] Other Uses of the Shaped Charge. As discussed above, the shapedcharge engine may be used to propel an aircraft, preferably including anaircraft that may travel in both atmospheric conditions, spaceconditions, or both. Further, the engine may be used as a direct exhaustdrive to propel a personal watercraft, boat, or other vehicle, or may beconfigured to drive a turbine to propel a car, boat, motorcycle, orother vehicles. In addition, the engine may be used as a bow thrusterfor boats, ships, or submarines.

[0088] In addition to propelling vehicles, the blast or pulse producedby the shaped charge engine is useful in a host of other applications.For example, the shock waves produced by the engine can be used forunderground rodent and pest extermination or the control of insects. Theshock wave from a single pulse may be used in avalanche control toinitiate movement of the potential avalanche, eliminating the need forartillery or explosives.

[0089] The shaped charge may also be used for a variety of demolitionpurposes. For example, it may be used as a rock breaker, to demolishbuildings, to fracture rocks in mining, to core and break concrete, orto remove ice from ships, bridges, or roads. In addition, the shapedcharge may have military uses as a mine that is both powerful andreusable. Ideally, the material is fragmented by directing one or moreshock waves toward it. Moreover, the demolition devices constructedusing the present shaped charge invention may be recovered and reused,unlike conventional demolition devices.

[0090] A wide range of tools may be created using the shaped chargeengine of the present invention. For example, the enormous shock wavesproduced may be put to use as a jackhammer or other impact tool, or maybe focused to produce cutting and etching devices. Hot paint, foam, ormetal may be sprayed in an alternate embodiment of the present inventionin which paint, foam, or metal is used as the additional mass injectedinto the blast chamber after ignition. Precisely focused and directedshaped charges may also be used in tree limb removal or weed trimming.Still further, the hot, powerful blasts may be put to use as a burner(such as in a furnace or boiler) or to remove snow from driveways,rooftops, or other locations. Moreover, hot, high pressure exhaust gasesmay be used to strip paint, varnish, and similar coatings.

[0091] In still further applications, a single pulse creates instantheat and pressure for differential pressure forming of metal without thenecessity of pre-heating the metal and without requiring compressors orother pressure storage devices. Similarly, pulses may be used to formmaterials by direct injection devices.

[0092] By placing projectiles in the exhaust stream, the shaped chargeengine can be used as a high-speed gun. Preferably, a gun barrel orsimilar launch tube extends from the exhaust port so that the exhauststream will propel the projectile in a controllable, straight path.

[0093] In a closed system, the shaped charge engine may be used tocreate and maintain pressure, adjusting the magnitude and rate ofpulsing to control the pressure. Alternatively, when configured to drivea turbine, the shaped charge engine may form a generator to produceelectricity.

[0094] Results from Actual Embodiments. As discussed above, serialinfusion and ignition of multiple charges of combustible mixture intothe hollow blast-forming chamber allow the detonation to be formed in apulsed manner. The pulse strength and/or frequency is dynamicallycontrolled during operation by varying the quantity and rate of infusingand igniting the serial charges of combustible mixture. Tests of anactual embodiment using the pulsed operation of the hypersonic exhauststream indicate that operating cycles over 100 Hz and exhaust gasvelocities as high as 30,000 feet per second are possible. Thus,independent variation is possible between gentle and powerful pulses andbetween slow and fast pulse.

[0095] As a pulsed jet or rocket engine for aerial vehicles, exhaust gasspeeds higher than possible with conventional turbine or rocketpropulsion units allow for smaller, lighter drives with fewer movingparts while potentially eliminating turbine blades, compressors, andexhaust nozzles. The pulsed hypersonic exhaust stream also reducesengine cooling requirements by providing pulsed rather than continuousoperation. The rapid burning and detonation assist in engine cooling byconverting the chemical energy of the combustible mixture quickly intohigh pressure with little wasted heat. This complete combustion alsoallows a higher efficiency of the engine and lower fuel use per pound ofthrust produced.

[0096] An actual embodiment of the present invention has beenconstructed and tested against a variety of other engines, demonstratingthe superior results. An engine capable of delivering 200 horse power(hp) constructed according to U.S. Pat. No. 6,000,214 to Scragg weighsapproximately 262 pounds and can produce 0.76 hp per pound of engineweight. An actual embodiment of the present invention that can delivermore than 200 hp weighs only 70 pounds and produces 2.86 hp/pound. Theshaped charge engine is also many times smaller, having a combustionchamber of 18 cubic inches compared with 560 cubic inches in a Scraggengine.

[0097] The advantages over gasoline, diesel, and Brayton cycle enginesare also substantial. In comparison to the actual 200 hp embodimentdiscussed above, equivalent 200 hp gasoline, diesel, and Brayton enginescan produce only 0.40, 0.22, and 1.0 hp/pound, respectively, and weighapproximately 500, 900, and 200 pounds. Consequently, an engineaccording to the present invention produces significantly more power ata much smaller size and weight than previous engines.

[0098] While the preferred embodiment of the invention has beenillustrated and described, many changes can be made without departingfrom the spirit and scope of the invention. Accordingly, the scope ofthe invention is not limited by the disclosure of the preferredembodiment. Instead, the invention should be determined entirely byreference to the claims that follow.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A shaped charge turbineengine, comprising: an inner housing; an outer housing joined to theinner housing to define a blast-forming chamber; a plurality of fuelinjectors adapted to inject fuel into the chamber at generallydiametrically opposite locations; and a central opening in theblast-forming chamber between the inner and outer housings defining aprimary convergence zone; whereby exhaust gases traveling through theprimary convergence zone from generally opposite locations collide at asecondary convergence zone substantially at the center of the shapedcharge engine to produce a moving charge of exhaust gas; a turbine rotorwithin said outer housing and fixed on a shaft, said turbine rotor beingsupported for rotation within the outer housing about a longitudinalaxis of said shaft, said turbine rotor having provided on a radiallyouter periphery thereof a plurality of turbine blades arranged in aseries extending circumferentially about said axis such that the movingcharge impacts the turbine rotor to rotate the shaft.
 2. The engine ofclaim 1, wherein the inner housing is generally annular in shape andincludes a substantially conical projection that, together with theouter housing, forms the primary convergence zone.
 3. The engine ofclaim 1, wherein the outer housing is substantially dome-shaped.
 4. Theengine of claim 1, wherein the blast-forming chamber is comprised of aplurality of generally opposed regions, each of which includes a fuelinjector, igniter, and an inner housing.
 5. The engine of claim 1,wherein the generally opposed sub-chambers are pivotable in the vicinityof an apex of the outer housing to enable the orientation of thesub-chambers to be varied between a position that directs initialexhaust products in a direction at an obtuse angle with the direction offinal exhaust through a position that directs initial exhaust productsin a direction at an acute angle with the direction of final exhaust. 6.The engine of claim 6, wherein the generally opposed sub-chambers arepivotable in the vicinity of the apex of the outer housing to enable theorientation of the sub-chambers to be varied between a position thatdirects initial exhaust products in a direction at an obtuse angle withthe direction of final exhaust through a position that directs initialexhaust products in a direction at an acute angle with the direction offinal exhaust.
 7. The engine of claim 5, wherein the generally opposedsub-chambers are pivotable in the vicinity of an apex of the outerhousing to enable the orientation of the sub-chambers to be variedbetween a position that directs initial exhaust products in a directionat an obtuse angle with the direction of final exhaust through aposition that directs initial exhaust products in a direction at anacute angle with the direction of final exhaust.
 8. The engine of claim1, wherein the inner housing further comprises projections adjustablyattached to the inner housing so that the projections may be movedtoward or away from the outer housing to decrease or increase the sizeof a pinch point defining the primary convergence zone.
 9. The engine ofclaim 8, further comprising a mass injector projecting at leastpartially into the chamber and connected to a mass source, the massinjector adapted to inject mass into the chamber following fuelcombustion.
 10. The shaped charge engine of claim 8 wherein the masscomprises water.
 11. The engine of claim 9, wherein the source of oxygencomprises separate sources of air and oxidizer.
 12. The engine of claim11, further comprising a sensor to detect the available presence of airmass and a controller in communication with the sensor to adjust thedelivery of oxygen to the chamber from all air to all oxidizer or amixture of air and oxidizer.